Ga-TC3-OGDOTA accumulates in apoptotic cells. (a) Design of [68Ga]Ga-TC3-OGDOTA. (b–f) Ga-TC3-OGDOTA (green) accumulation in neuronal cell cultures treated with CPT. (b) Ga-TC3-OGDOTA predominantly accumulated in cells showing apoptosis by characteristic nuclear morphology (DAPI, blue); minor Ga-TC3-OGDOTA staining was also detected in dead cells, positive for PI (red). Thick arrows point to apoptotic cells, arrowheads to healthy cells, and thin arrows to dead cells. (c) Quantification of cells positive for apoptotic nuclear morphology, Ga-TC3-OGDOTA, and PI. (d) Distribution of Ga-TC3-OGDOTA cells (OG+) within apoptotic, dead, and healthy neurons. (e, f) Ga-TC3-OGDOTA fluorescence in cultures treated with CPT or CPT and an apoptosis inhibitor Z-DEVD-FM. (e) Representative images for each treatment. (f) Quantification of Ga-TC3-OGDOTA-positive cells.